Re: [PATCH] clk: mxs: ensure that i.MX28's ref_io clks are not operated too fast

[Stefan Wahren <stefan.wahren@i2se.com>]

Am 05.05.2017 um 09:49 schrieb Stefan Wahren:
> Hello Uwe,
>
> Am 05.05.2017 um 09:25 schrieb Uwe Kleine-König:
>> Hello Stefan,
>>
>> On Thu, May 04, 2017 at 02:25:07PM +0200, Stefan Wahren wrote:
>>>        ref_io1                            1            1  
>>> 320000000          0 0
>> That means your ref_io1 is running at 320 MHz which my patch should
>> prevent. Are you sure it is applied?
> sorry for the mess in the dumps.
>
> Your patch works fine regarding to ref_io1. I made 3 dumps:
>
> 1. without any patch ( ref_io1 320000000 )
> 2. with my ref_xtal patch ( ref_io1 288000000 )
> 3. with your patch ( ref_io1 288000000 )
>
> I assume you looked at the wrong dump.
>

Uwe and i made some investigations regards to this issue. The busy bit
of the HW_CLKCTRL_SSP3 was high after boot up, but this shouldn't be the
case. I have the suspicion that there is an issue during clock init or
in the mxs clock driver.

Duckbill (Linux 4.11 Mainline)

HW_SSP2_TIMING    0x80014070 00000209
HW_CLKCTRL_HBUS   0x80040060 00000003
HW_CLKCTRL_SSP0   0x80040090 00000005
HW_CLKCTRL_SSP1   0x800400A0 80000001
HW_CLKCTRL_SSP2   0x800400B0 00000002
HW_CLKCTRL_SSP3   0x800400C0 A0000001
HW_CLKCTRL_EMI    0x800400F0 00000102
HW_CLKCTRL_FRAC0  0x800401B0 5E5B5513
HW_CLKCTRL_CLKSEQ 0x800401D0 00004104

@Uwe: Additionaly applying "spi: mxs: implement runtime pm" to this
patch also doesn't fix the bit error.

Regards Stefan